抄録
Closure behavior and growth characteristics of a wide range of fatigue cracks including incipient short cracks and elastic-plastic long ones extending beyond general yielding were investigated by using the unloading elastic compliance method, and in situ direct observations of propagating fatigue cracks were made with a scanning electron microscope to study their microscopic crack growth modes.
The effective stress intensity range ΔKeff was found the most governing parameter of growth rate for all kinds of fatigue cracks, except when general yielding took place and monotonic deformation became significant. It was found that the microscopical crack growth mode varied depending on growth rate and the crack opening ratio U was related to growth mode.
